Kullu (Himachal Pradesh), July 23 (IANS): At least six people were killed and 12 others injured when a private tourist bus from Punjab skidded off the road and fell into the swollen Parvati river in Himachal Pradesh's Kullu district on Thursday, police said.

Twenty-nine passengers were still missing and their chances of survival were bleak as the bus was still untraceable.

Officials said the toll could rise as the bus had 51 passengers -- a majority of them from Punjab's Barnala and Mansa towns who were travelling to a famous Sikh shrine in Manikaran.

The bus met with the accident in Sarsari village on the Bhuntar-Manikaran road, some eight km from Bhuntar, Deputy Commissioner Rakesh Kanwar told IANS.

He said six bodies were fished out and a rescue operation was on.

"The bus is still untraceable. Most the bodies might be still stuck in the bus or washed away," he said.

The cause of the accident was yet to be ascertained, he added.

The injured were admitted to government hospitals in Kullu, some 200 km from Shimla.

The government has summoned divers of the Bhakra Beas Management Board (BBMB) to locate the bodies.

Governor Kalyan Singh and Chief Minister Virbhadra Singh mourned the deaths.

The chief minister directed the district administration to intensify the search operation, besides providing all possible assistance to the injured.